Spiders in the Stratosphere ?

of unsubstantiated claims that spiders have been found in the stratosphere. Obviously, this would be damaging to the view that the biological entities we isolate from the high stratosphere are too large to be elevated from Earth to this region. I recently did a Google Book Advanced Search to see if I could find the origin of the claim that ballooning spiders can be found in the stratosphere. Here are the vague claims:

Long before the first balloonists or stratosphere flyer left old terra firma, young spiders were soaring into the blue”.

Anon (1934). Chemistry Leaflet vol.8, p.561.

Most spiders float at heights below 200 feet, but some have been found manoeuvring in the stratosphere.

Anon (1957). American Mercury, vol.84, p55.

Tiny spiders and insects have been floating above Mount Everest and into the stratosphere.

Wallace (1987). Life in the Balance, Harcourt Bruce.

In experiments carried out by the naturalist/filmmaker, David Attenborough, balloon spiders were collected above the Earth’s atmosphere in the UPPER layer of the stratosphere (my emphasis).

Filmer (1991). Filmer’s Spiders, Random House.

I was giving up on the possibility that I might find reference to an actual height at which spiders are apparently found when I came across the following:

This gives a height at which such isolation has occurred at 5000 meters, clearly well below the stratosphere at which our biological entities are isolated, although again no reference is given to the source of this claim. It seems therefore that I can relax about stratospheric spiders.